The present invention relates broadly to conveyors, and more particularly, to sheet stacking conveyors which have at least one end which moves in an upright direction in connection with the deposit of sheets in overlying relationship to form a stack. A number of such conveyors have been described in the patent literature. For example, see U.S. Pat. Nos. 2,660,432; 2,901,250; and 3,658,322.
In the processing of rigid sheets, such as sheets of corrugated paperboard, it is conventional to move the sheets on a conveyor from a sheet forming machine to a palletized stack for subsequent operations. In forming said stack, a stacking conveyor ejects the sheets sequentially one upon the other while the discharge end of the stacking conveyor rises in synchronism with the increase in height of the stack.
It is common for such stacks to reach a height of 6 feet or more. The discharge end of the stacking conveyor may rise to a height greater than the height of a workman. If a workman happened to be under the discharge end of the stacking conveyor at a moment when a chain or other component of the supporting structure failed, the falling conveyor might cause injury to the workman. Accordingly, there is a need for a device to prevent such conveyors from accidentally dropping and yet not interfere with operation of the conveyor.